2015 Polaris ranger 570 XP
If it were my Ranger I would put it up on stands, start it, put it in gear with someone on the throttle and slide under it to see if I could locate the source of the noise. Afterwards, I would shut it down and start manually inspecting things by shaking and tugging on them. It may be a U-joint or even the yoke that slides on to the front differential input shaft or transmission output shaft (snorkel shaft) that has become worn enough to flop around on the shaft. It could also be bad CV joints that are also dry. Look for a torn boot and loss of lube and be certain to inspect both inboard and outboard ends of the driveshafts. Grab the wheels and tires and move them around to feel for loose wheel bearings or bad ball joints. I'd check the back too, for two reasons: 1) if the front is worn enough to make noise the back has gone the same number of miles and may be worn as well. 2) Drive train noises can be transmitted throughout the drive train and really fool you as to where it is originating.